The invention relates to a support with adjustable arch, especially a lumbar support for seats, in particular motor vehicle seats and chair back rests as well as for any type of bed, the structure of which comprises an arching element and an adjustment device for setting and readjusting the arching of the arching element.
Arching elements are known e.g. from DE-OS 25 41 559, DE 42 32 679 C1 and DE 44 44 803 C2. Virtually all known arching elements have in common that the stiffness of the arching element increases as the arching increases and the surface area by which it bears against the body to be supported, is progressively decreased until a linear line of contact is attained, which, at least after prolonged use, results in discomfort to the user and even pain. These problems accumulate if, in addition, the level of the arching element is wrongly adjusted.
From DE-OS 25 41 559 a back rest is known, which provides an extendible and retractable rigid support panel fitted to two supports in the form of leave springs, which are movable in relation to one another and together. In this case, the support surface is of constant size regardless of its extended or retracted state and is also, in principle, of constant rigidity.
From U.S. Pat. No. 5,651,587, forming the generic clause of claim 1 and from corresponding DE 42 32 679 C1, but also from DE 43 20 105 C1 back rests are known having an adjustable arching element, and which comprise an additional pelvic support, connected to the arching element. In this manner an improved large area support, in particular in the direction of the pelvis is attained, even if arching is extensive, in particular, if according to a working example a resiliently flexible panel is provided instead of a rigid one, but which is then spring-loaded on one side. However, this embodiment is complicated to manufacture and due to the large number of components required, is also expensive.
From DE 44 44 803 C3 a resilient arching element of plastics is known, manufactured in one piece and therefore simple to manufacture, into which parts of the adjustment device have been integrated resulting in the aforementioned problems in the event of pronounced arching.
It is an object of the invention to develop a support, arching of which is adjustable according to the generic clause of claim 1, in such a manner that a resilient and large area contact with the user is provided, even in the event of extreme arching, where this support should, in addition, be easily and rapidly manufactured and assembled in a cost-effective manner.
This object is attained in a support with adjustable arch having the characterising integers of claim 1. By this solution an arching element is attained from an archable element member and a panel, in which case the panel connected thereto, due to its low surface area connection, is subjected to little or no arching and, regardless of the degree of arching, always acts in a resilient and thereby large area manner.
The subsidiary claims embrace advantageous further developments of the subject of claim 1, the respective advantages of which are further explained in the description of working examples of the invention.